German ASELT sensors, ASELT models, ASELT prices

ASELT sensors are the direct source of information for the entire machine vision system. They mainly consist of one or two image sensors, sometimes accompanied by light projectors and other auxiliary equipment. The main function of a vision sensor is to acquire the raw images that the machine vision system needs to process. Image sensors can use laser scanners, line-scan and area-scan CCD cameras or TV cameras, as well as newly emerging digital cameras.

ASELT sensor classification

1) Laser speed measurement: With the rise of modern precision manufacturing and the demand for cost savings, non-contact speed sensors will gradually replace contact speed sensors. Currently, the most accurate and commonly used non-contact laser speed sensor on the market is the ZLS-Px aberration speed sensor. The aberration speed sensor has two ports: an emission port that emits LED light sources, and a high-speed imaging port that achieves CCD area high-speed imaging comparison. By comparing images at two points in time within an extremely short period, it determines the distance the object has moved. Combined with internal algorithms, it outputs the object's speed in real time. As shown in the figure, (1) is the LED light emission port, (2) is the camera reception port, (3) and (4) are terminal blocks, and (5) are mounting screw holes. (1) The LED light emission port emits laser light toward the measured object; after reflection, it reaches the (2) camera reception port. Upon receiving the signal, it is transmitted to the signal processor, which calculates the speed using algorithms. The ZLS-Px aberration speed sensor can simultaneously measure speed and length in two directions. It can detect not only whether the measured object has stopped but also its direction of motion. Mount the sensor on a stable bracket to ensure that the rotating object does not produce excessive vibration during rotation, thereby allowing measurement of the rotation angle and speed of the rotating object. 2) Radar speed measurement: Traditional speed measurement mostly involves rotational and linear motion speed measurement. However, there are many irregular speed measurement scenarios in industrial automation, such as athlete speed measurement, traffic vehicle speed measurement, and golf ball speed measurement. Radar speed sensors can meet these requirements.

ASELT sensor principle

A transmissive speed sensor consists of a slotted or notched disk, a light source, and a phototube. When the disk rotates with the measured shaft, light can only reach the phototube through the holes or notches. When the phototube is illuminated, its reverse resistance is very low, outputting an electrical pulse signal. When the light source is blocked by the disk, the phototube's reverse resistance is very high, and no signal is output. Thus, based on the number of holes or notches on the disk, the rotational speed of the measured shaft can be determined. The usual number of disk holes or notches is unclear in the source, so when the measured shaft completes one revolution, the photoelectric converter outputs 60 pulse signals. If the time base signal of the electronic counter is set to 1s, the rotational speed of the measured shaft can be read directly. The principle of a reflective speed sensor is similar to that of a transmissive one; it converts changes in received light into electrical signals via a phototube, but it obtains pulse signals through light reflection. Typically, reflective material is attached to the measurement area of the measured shaft to form a reflective surface. Commonly used reflective materials include specialized speed-measuring reflective tape (adhesive tape); aluminum foil or other reflective materials can also be used. Sometimes, white paint is applied to the measured area to serve as a reflective surface. The projector and reflective surface must be properly configured, typically with a distance of 5-15M between them. When the measured shaft rotates, the photoelectric element receives pulsating light and outputs corresponding electrical signals to the electronic counter, thereby measuring the rotational speed of the shaft. The waveform of the output signal from photoelectric speed sensors is relatively regular, close to a standard square wave, with almost no interference signals generated. However, vibration in transmissive types can reduce the lifespan of the light source, making them unsuitable for conditions with strong vibrations. Reflective types have no mechanical connection with the measured shaft and are convenient to use.

ASELT sensor industry applications

1) Modern cars are generally equipped with engine control, autonomous driving, ABS, TRC, automatic door locking, active suspension, guidance systems, electronic instruments, and other devices, all of which require vehicle speed signals. Therefore, the accuracy and stability of the output signals from speed sensors will greatly affect these control units. Automotive speed sensors often adopt a Hall-effect structure. A Hall speed sensor is a magnetoelectric sensor based on the Hall effect, featuring high magnetic field sensitivity, stable output signals, high frequency response, strong anti-electromagnetic interference capability, simple structure, and ease of use. It mainly consists of permanent magnets with a specific number of pole pairs (generally 4 or 8 pairs), Hall elements, a rotating mechanism, and input/output connectors. Its working principle is that when the sensor's rotating mechanism is driven externally, it rotates the permanent magnet, causing periodic changes in the magnetic field passing through the Hall element. This induces changes in the output voltage of the Hall element, which are processed by subsequent circuits to form stable pulse voltage signals as the output of the speed sensor. Key electrical technical parameters of Hall-structure speed sensors include high/low output voltage, duty cycle, period, rise time, fall time, and pulses per cycle. To ensure product performance reliability, these parameters must be quantitatively tested before factory shipment. Test systems featuring integration and intelligence, efficient automatic measurement, software calculation, and graphical or tabular display of results are increasingly favored by automotive speed sensor manufacturers. A comprehensive testing device has been developed for performance measurement of common Hall-effect vehicle speed sensors. Considering costs, the high-speed counter port of a microprocessor is used for data acquisition from the vehicle speed sensor, while software control handles data calculation and graphical display processing. The completed testing device offers advantages such as high testing accuracy, reliable data communication, a user-friendly graphical interface, strong anti-interference capability, simple and intuitive testing processes, and low system development costs. It has good market promotion potential, indicating significant application prospects for speed sensors in vehicle speed detection. 2) Speed sensors for belt conveyors adopt Hall sensors, which utilize the Hall effect for magnetoelectric conversion. Since the discovery of the Hall effect in 1879, it has undergone more than 100 years of development history. However, its application gained attention and widespread adoption in the 50s of this century due to the rapid development of microelectronics, leading to the continuous development of various Hall elements. China began increasing research on Hall elements in the 20s of the 70th century. After nearly several decades of research and development, it is now possible to produce Hall elements with various performances, such as standard type, high sensitivity type, low temperature coefficient type, temperature/magnetic measurement type, and switch type. Due to the characteristics of Hall sensors—high sensitivity, good linearity, high stability, small size, and high temperature resistance—they are widely used in various industrial fields, including non-electrical quantity measurement, automatic control, computer devices, and modern military technology.

Weidou Intelligent Technology specializes in selling German ASELT sensors, ASELT proximity sensors, ASELT distance sensors, ASELT vision sensors, ASELT displacement sensors, ASELT torque sensors, ASELT speed sensors, ASELT photoelectric sensors, ASELT position sensors, ASELT angle sensors, ASELT tactile sensors, ASELT temperature sensors, ASELT pressure sensors, ASELT flow sensors, ASELT level sensors, ASELT motion sensors, and ASELT process sensors. All products are original imports from Germany. We welcome inquiries and orders from customers.